Going For Gold To Detect Prostate Cancer

November 20, 2009

Scientists from the USA’s Northwestern University have developed gold and magnetic nanoparticles that has a 300% better chance of detecting prostate cancer than conventional methods and could also track a wide variety of diseases.

The nanoparticles can detect prostate specific antigens (PSA – a protein produced by the prostate), and these are the leading indicator of prostate cancer, at far lower levels than is possible with existing blood tests. The new technology could not only save the lives of millions of men but also be adapted to detect or monitor a wide variety of diseases, from HIV to CJD.

When a man has had a cancerous prostate removed his PSA level drops to below what is currently detectable. At the moment prostate cancer testing is done using two methods: a manual examination of the prostate or/and a blood test. The blood is tested for the presence of PSA, and men with prostate cancer typically have a higher level of PSA in their blood than normal.

The old test directly measured the amount of PSA in the blood, but this new test will indirectly measure PSA levels by adding two types of nanoparticles to the blood sample. First, spherical gold nanoparticles tipped with antibodies bind to one side of the PSA proteins. Next, magnetic nanoparticles bind to the other side, basically sandwiching the PSA.

A magnet then draws the PSA and nanoparticle sandwich out of the blood. The nanoparticles then separate, which in turn can spur the release of thousands of DNA strands.

Since every single PSA particle can result in thousands of DNA pieces, even the tiniest amounts of PSA can be easily detected. Compared with the existing PSA blood tests, this new method is 300 percent more sensitive.

The bonus here is that usually a man who has had prostate surgery may have to wait up to seven years before he definitively knows whether he is cancer free. The new test would shave years off that wait.

Also, by changing the antibodies that coat gold and magnetic nanoparticles, this technology can be easily adapted to detect or monitor virtually any other disease.